Nebulae Series #2 Diffuse Nebulae

This is the Omega Nebula. It almost looks like a picture taken of the sky hear on Earth. This nebula is an example of our next type of nebula: the diffuse nebula.

The Diffuse nebulae are a collection of two subcategories of nebulae: the reflection and emission nebulae. This is, by far, the biggest category of nebulae in the universe. The term diffuse refers to a nebula with not specific shape or size. It essentially means it's just a massive cloud of gas and dust.

The classifications of emission and reflection refer to the way the nebulae shed their light. Emission nebulae contain ionized gases that create their light. Reflection nebulae produce hardly any light, but are largely visible by reflecting light from the stars. There is a subcategory of these as well known as dark nebulae. They do not produce loght at all, but are visible, and notable, by the fact that their darkness creates their visibility. The Horse Head Nebula, attached below, is a dark nebula. Note the distinct shape formed by the black.